Hello i had kind of the same problem, when i did a children of a children bp and added a variable called by them, it make my editor crash. Here is the error message i got:
Assertion failed: ((UObject*)ContainerPtr)->IsA(GetOwner()) [File:D:\build++UE5\Sync\Engine\Source\Runtime\CoreUObject\Public\UObject\UnrealType.h] [Line: 714]
‘Default__REINST_SKEL_BP_BaseClothes_C_31’ is of class ‘REINST_SKEL_BP_BaseClothes_C_31’ however property ‘TriggerInteract’ belongs to class ‘SKEL_BP_BaseInteract_C’
Maybe the problem wasn’t having a child of a child blueprint and modifying a structure that was called in them, but rather compiling and saving. I no longer had this problem by removing the automatic save and manually compiling and saving the blueprints. To avoid the pain of compiling everything by hand, I simply installed the refreshallnodes plugin, which does it for me.
I didn’t see anyone respond to my problem so hope it help some of you.